In the following, the term “plaster” is intended to mean self-adhering, flat coverings which are to be applied to the human skin. The plasters can be of a single- or multi-layer construction and can consist of films, woven fabrics or non-woven fabrics in combination with self-adhering polymers. In addition, the plasters can contain any desired pharmaceutical or cosmetic active agents or also be free of active agent. They can be applied to healthy or damaged skin.
The adhesive of the plasters generally exhibits a flowability which is sufficient so that it can flow around unevennesses or roughnesses of the skin and ther by result in a good bond to the skin. Very “hard” adhesives which have glass transition temperatures of more than 10 to 20° C. usually do not adhere well to the skin. On the other hand, however, if the adhesive exhibits good flow behavior, a small amount of adhesive can escape at the cut edges of the final plaster during storage or when it is worn (so-called “cold flow”). The adhesive which has escaped can, e.g., adhere to the packaging material during storage or adhere to the surrounding clothing or other articles which are in contact to the skin during the duration of application to the skin.
After having been worn for some time such plasters exhibit a cosmetically very displeasing “dirty fringe” which is generally formed by fibers of clothing or other particles which adhere to the adhesive composition which escapes at the cut edge. The dirty fringe can occur directly on the skin outside of the plaster or under the external edges of the plaster.